Over the summer of 2013 several very well made corrugated plastic boats were featured on DIY sites and on r/buildaboat. It all seemed very simple to do and I’d always wanted my own boat to fool around with so I thought why not! Corrugated plastic in large sheets were easy to come by once a little research had been done and the only other materials which were required were reusable zip-ties and some kind of propulsion device: a paddle or a small trolling motor. Much credit is owed to the pioneers of this strange art!


Corrugated plastic (AKA Coroplast) was the material of choice for forming the hull in all of the previous examples of these foldable boats. Mine would be no exception to this pattern, and so I set out to source the largest readily available sheet of corrugated plastic I could find. The Discount Builders Supply store in the Mission provided these boards in generous sizes. Purchasing two sheets, I slowly walked home with them, catching all sorts of cross winds with my planks of white plastic. A better way to transport these things is highly recommended.

The first sheet was to be used as the hull and the second was for the furniture that could line the interior of my watercraft (seat, bracing, internal hull).

This boat also had to be as simple as possible since that was only way it could end without abject failure. With regard to this, I decided against any means of moving the boat which was not a paddle. Luckily, I found a nice paddle on Amazon for the wallet-pleasing price of $20 taxes included!

Scale Models

The first thing in creating any sort of product is figuring out how things will come together in a way which satisfies all your needs. With a foldable boat this means creating a scale model that has a contour which is simple and reasonably easy enough to fold manually. Here are two of the better folds I tried:

The style on the left was chosen as the keel fold would be hard enough to cease once, let alone twice as on the kayak-like right model. The keel was folded in a way which minimized any seam contact with the water line. A “milk-carton” style fold was used for the back to make it easier to refold.

Initial Folding

With the combined effort of a small dog and two zesty humans, the boat slowly came together according to the pattern that was tested in the scale model. Below you can see the progress:

Fold photos

Maiden voyage and success!

My lovely friends were convinced I was going to drown in my newly crafted vessel once it had been unfolded to stow away for transport and refolded for use. Survival was fairly certain in my opinion, so we decided to call the wager by launching the Coroplast boat at Lake Merced, about 20 minutes south of SF.

Curiosity brought a fellow water-sport enthusiast over to help us with the launch, I was especially thankful as the winds were strong that day.

Without further ado, these follow photos prove that I didn’t drown!

Launch photos

The project was a great success and now we have experience building a simple boat! Paddling was tough exercise though so I might just stick to designing and launching them. Very much looking forward to the next boat build!